Showing papers on "Tissue culture published in 2002"

Methods of tissue engineering

Abstract: Contributors. Foreward. Preface. SECTION I: METHODS FOR CELL AND TISSUE CULTURE Regulatory Issues and Standardization. Cell Isolation and Selection. Maintenance of Primary and Early Passage Cultures. Cell Quantitation and Characterization. Adventitious Agents and Chemical Toxicity. Culture Environments: Cell-Polymer-Bioreactor Systems. Culture Environments: Microarrays. Culture Environments: Micropatterned Cell Cultures and Cocultures. Epithelial Cell Culture: Cornea. Epithelial Cell Culture: Breast. Liver Cell Culture and Lineage Biology. Epithelial Cell Culture: Pancreatic Islets. Epithelial Cell Culture: Tracheal Gland Cells. Epithelial Cell Culture: Kidney. Epithelial Cell Culture: Gastrointestinal Tract. Epithelial Cell Culture: Urothelium. Epithelial Cell Culture: Prostate. Epithelial Cell Culture: Three-Dimensional Cervical System. Epithelial Cell Culture: Vaginal Cell Reconstruction. Mesenchymal Cell Culture: Adipose Tissue. Mesenchymal Cell Culture: Smooth Muscle. Mesenchymal Cell Culture: Cardiac-Derived Muscle Cells. Mesenchymal Cell Culture: Functional Mammalian Skeletal Muscle Constructs. Mesenchymal Cell Culture: Instrumentation and Methods for Evaluating Engineered Muscle. Mesenchymal Cell Culture: Cartilage. Mesenchymal Cell Culture: Bone. Mesenchymal Cell Culture: Endothelial Cell Tissue Engineering. Mesenchymal Cell Culture: Blood Vessels. Neuroectodermal Cell Culture: Endocrine Cells. Neuroectodermal Cell Culture: Glia and Neurons. Gonad Cell Culture: Testis. Gonad Cell Culture: Ovarian Cells. Stem Cell Culture: Pluripotent Stem Cells. Stem Cell Culture: Neural Stem Cells. Stem Cell Culture: Liver Stem Cells. Stem Cell Culture: Muscle Stem Cells. Stem Cell Culture: Endothelial Progenitor Cells for Regeneration. Stem Cell Culture: Mesenchymal Stem Cells From Bone Marrow. Stem Cell Culture: Chondrogenic Stem Cells. Stem Cell Culture: Hematopoietic Stem Cells. Stem Cell Culture: Lymphoid Cells. SECTION II: METHODS FOR CELL DELIVERY VEHICLES Modification of Natural Polymers: Collagen. Modification of Natural Polymers: Collagen-Glycosaminoglycan Copolymers. Modification of Natural Polymers: Albumin. Modification of Natural Polymers: Hyaluronic Acid. Modification of Natural Polymers: Fibrinogen-Fibrin. Modification of Natural Polymers: Chitosan. Polymers Biosynthesized by Microorganisms: Polyhydroxyalkanoates. Synthesis of Synthetic Polymers: Aliphatic Carbonate-Based Polymers. Synthesis of Synthetic Polymers: Dioxanone- and Dioxepanone-Based Polymers. Synthesis of Synthetic Polymers: Polyphosphazenes. Synthesis of Synthetic Polymers: Poly(Anhydrides). Synthesis of Synthetic Polymers: Poly(Ortho Esters). Synthesis of Synthetic Polymers: Poly(Amino Acids). Synthesis of Synthetic Polymers: Poly(Propylene Fumarate). Synthesis of Hydrogels: Alginate Hydrogels. Synthesis of Hydrogels: Environmentally Sensitive Hydrogels Based on N-Isopropylacrylamide. Processing of Polymer Scaffolds: Solvent Casting. Processing of Polymer Scaffolds: Membrane Lamination. Processing of Polymer Scaffolds: Freeze-Drying. Processing of Polymer Scaffolds: Polymer-Ceramic Composite Forms. Processing of Polymer Scaffolds: Phase Separation. Processing of Polymer Scaffolds: Polymerization. Processing of Polymer Scaffolds: Gas Foam Processing. Cell-Synthetic Surface Interactions: Self-Assembling Biomaterials. Cell-Synthetic Surface Interactions: Targeted Cell Adhesion. Cell-Synthetic Surface Interactions: Physiochemical Surface Modification. Microencapsulation Methods: Agarose-PSSa. Microencapsulation Methods: Alginate (CA2+-Induced Gelation). Microencapsulation Methods: Alginate-Poly(L-Lysine). Microencapsulation Methods: Alginate-Poly(Lysine)-Poly(Ethyleneimine)-Protamine Sulfate-Heparin. Microencapsulation Methods: Glycosaminoglycans and Chitosan. Microencapsulation Methods: Polyacrylates. Microencapsulation Methods: Poly(Vinyl Alcohol) (PVA). Microencapsulation Methods: PMCG Capsules. Microencapsulation Methods: Chitosan and Alginate. SECTION III: METHODS FOR ENGINEERING CELLS AND TISSUES Fetal Cell Culture. Breast Reconstruction. Blood Vessel Substitute. Small-Diameter Vascular Grafts. Cardiac Tissue. Cardiac Valves and Arteries. Cornea. Alimentary Tract. Monitoring Metabolic Activity and Differentiated Function in a Bioartificial Liver Device. Blood Cell Substitutes. Liver. Extracorporeal Kidney. Intracorporeal Kidney. Urethral Tissue. Penis. Testes. Cartilage Recontruction. Phalanges and Small Joints. Meniscus. Cell-Based Therapies for the Treatment of Articular Cartilage Injury. Cell-Based Therapies for Bulking Agents. Myoblast Transplantation. Skeletal Muscle. Vision Enhancement Systems. CNS Grafts for Treatment of Neurological Disorders. Peripheral Nerve Regeneration. Spinal Cord. Cryopreserved Dermal Implants. Bilayered Skin Constructs. Uterus. Jawbone. Periodontal Applications. Author Index. Subject Index.

Alteration of amino acids in VP2 of very virulent infectious bursal disease virus results in tissue culture adaptation and attenuation in chickens.

Abstract: Reverse genetics technology offers the possibility to study the influence of particular amino acids of infectious bursal disease virus (IBDV) on adaptation to tissue culture. Genomic segments A and B of the very virulent (vv) IBDV field strain UK661 were completely cloned and sequenced, and the strain was rescued from full-length cDNA copies of both segments (UK661rev). Using site-directed mutagenesis, alteration of a single amino acid in the segment A-encoded VP2 (A284T) resulted in a limited capacity of UK661 to replicate in tissue culture. Additional alteration of a second amino acid (Q253H) increased replication efficiency in tissue culture. The second mutant (UK661-Q253H-A284T) was used to infect chickens and results were compared with UK661 and UK661rev. Whereas UK661 and UK661rev induced 100% morbidity and 50–80% mortality, UK661-Q253H-A284T proved to be strikingly attenuated, producing neither morbidity nor mortality. Moreover, UK661-Q253H-A284T-infected animals were protected from challenge infection. Thus, alteration of two specific amino acids in the VP2 region of IBDV resulted in tissue culture adaptation and attenuation in chickens of vvIBDV. The data demonstrate that VP2 plays a decisive role in pathogenicity of IBDV.

Efficiency, genotypic variability, and cellular origin of primary and secondary somatic embryogenesis of Theobroma cacao L.

Abstract: Summary The development of efficient tissue culture systems for cacao holds the potential to contribute to the improvement of this tropical crop by providing a rapid and efficient vegetative propagation system for multiplication of elite genotypes. It may also find application in facilitation of germplasm movement across quarantine borders, enhancement of germplasm conservation via cryo-preservation, and development of genetic transformation systems. Somatic embryogenesis using floral tissue explants was previously the only tissue culture procedure for regeneration of cacao. We report the development of a secondary embryogenesis system utilizing primary somatic embryo cotyledon explants, which results in up to a 30-fold increase in somatic embryo production compared to primary somatic embryogenesis. The influence of genotype on the efficiency of the system was evaluated. To understand the cellular origins and developmental pathways operative in this system, we investigated the morphological changes occurring over time using light and scanning electron microscopy. While primary embryos arise from clusters of cells forming embryonic nodules, secondary embryos arise predominantly from the division of single cells, in a pathway reminiscent of zygotic embryogenesis. These results have important significance to the application of tissue culture to cacao improvement programs.

Dilute Povidone-Iodine Solutions Inhibit Human Skin Fibroblast Growth

Abstract: background. Povidone-iodine solutions are widely used and highly effective antiseptics. Although commonly used at full strength, this concentration appears to be toxic to the cells involved in wound healing. Few systematic studies of povidone-iodine toxicity have been reported. The effects of various dilutions of 10% povidone-iodine solution on the growth of human diploid fibroblasts were assessed using in vitro cell culture. objective. The purpose of this study was to systematically evaluate the toxicity of povidone-iodine on living cells using an in vitro model. methods. Adult skin fibroblasts and fetal lung fibroblasts were subcultivated at various seeding densities of 3000–10,000 cells/cm2 and grown in polystyrene tissue culture flasks under an atmosphere containing 5% O2, 5% CO2, and 90% N2. Cells were grown in a medium containing various concentrations of povidone-iodine (1%, 0.1%, 0.025%, 0.01%, and 0%). Cell attachment was reduced by 0.1% and 1% povidone-iodine in our initial studies; subsequent experiments were performed by changing the medium to contain the povidone-iodine 24 hours after seeding. Growth curves were performed by counting triplicate cultures every 48 hours for 250–300 hours. results. Fibroblast growth was progressively retarded at 0.01% and 0.025%, and totally inhibited by 0.1% and 1% povidone-iodine solutions. Partial recovery of cell growth after limited exposure of cultures to dilute solutions of povidone-iodine was noted. conclusion. This study shows that even dilute solutions of povidone-iodine are toxic to human fibroblasts. The results indicate that caution should be used when povidone-iodine is placed on an open wound, and that prolonged contact with viable uncontaminated tissue should be avoided.

Establishment of a reproducible tissue culture system for the induction of Arabidopsis somatic embryos

Abstract: Somatic embryogenesis is an example of totipotency and is used as a model system for studying embryogenesis. A reproducible tissue culture system was established for the large-scale induction of Arabidopsis somatic embryos. The method allows maintenance of high embryogenic competence over a one-year period. Using this tissue culture system, the expression of embryo-specific genes (ABI3, LEC1, FUS3) was detected in embryogenic cells and somatic embryos. Exogenous application of abscisic acid enhanced the expression of some late-embryogenesis-abundant (LEA) protein genes in somatic embryos. The experiments show that the method can be used to obtain sufficient amounts of embryogenic material for basic molecular analyses.

Cells in human postmortem brain tissue slices remain alive for several weeks in culture

Abstract: Animal models for human neurological and psychiatric diseases only partially mimic the underlying pathogenic processes. Therefore, we investigated the potential use of cultured postmortem brain tissue from adult neurological patients and controls. The present study shows that human brain tissue slices obtained by autopsy within 8 h after death can be maintained in vitro for extended periods (up to 78 days) and can be manipulated experimentally. We report for the first time that 1) neurons and glia in such cultures could be induced to express the reporter gene LacZ after transduction with adeno-associated viral vectors and 2) cytochrome oxidase activity could be enhanced by the addition of pyruvate to the medium. These slice cultures offer new opportunities to study the cellular and molecular mechanisms of neurological and psychiatric diseases and new therapeutic strategies.—Verwer, R. W. H., Hermens, W. T. J. M. C. Dijkhuizen, P. A., ter Brake, O., Baker, R. E., Salehi, A., Sluiter, A. A., Kok, M. J. M., ...

Studying actin-dependent processes in tissue culture.

Abstract: The cytoskeletal organization of cells that are grown in tissue culture is often very different from that of cells in living organisms This casts some doubt as to whether information that comes from studying actin-dependent cellular processes — such as cell motility or differentiation — in cells that are cultured under these conditions is physiologically relevant Studies on cells grown in improved two-dimensional- and three-dimensional-culture systems that closely mimic the in vivo extracellular-matrix environment should provide a more accurate picture of actin-cytoskeletal function in the living organism

Insect Cell Culture in Microfluidic Channels

Abstract: Microfluidic channels were constructed out of polydimethylsiloxane (PDMS) and used as culture vessels for ovary cells from the fall armyworm, Spodoptera frugiperda, (Sf9). PDMS allows cells to be visually inspected and provides excellent permeability to oxygen and carbon dioxide. Cells were grown in static culture conditions and observed every 24 hours for seven days. The growth rate in microchannels of varying volume (2.8 μl to 0.6 μl) was significantly slower in two sets of experiments (P<0.05 and P<0.001) than in a 25 ml tissue culture flask.

Jak2 is an essential tyrosine kinase involved in pregnancy-mediated development of mammary secretory epithelium.

Abstract: The PRL receptor (PrlR) and the signal transducer and activator of transcription 5a (Stat5a) are essential for the proliferation and differentiation of mammary epithelium during pregnancy. Based on tissue culture cell experiments, Jak2 is the tyrosine kinase responsible for the phosphorylation of both the PrlR and Stat5. We have now used a genetic approach to test the role of Jak2 in the mammary gland, a PrlR-responsive tissue. Because Jak2-null embryos die at E12.5, we transplanted Jak2-null mammary anlagen into cleared fat pads of wild-type mice and investigated epithelial development during pregnancy. In the absence of Jak2, no secretory alveoli were present at parturition, and epithelial cell proliferation was reduced by 95% after an acute hormone treatment. Furthermore, the Na-K-Cl cotransporter, a ductal marker, was maintained in Jak2-null epithelium and the sodium-phosphate cotransporter type IIb, a secretory cell marker, was absent. Nuclear Stat5a was only observed in a few epithelial cells in Jak...

Effects of tissue culture conditions and explant characteristics on direct somatic embryogenesis in Oncidium `Gower Ramsey'

Abstract: The effects of tissue culture conditions and explant characteristics on direct somatic embryogenesis were studied on Oncidium `Gower Ramsey'. Embryo formation was significantly affected by explant position. Leaf tip segments had a significantly higher embryogenic response than other segments of leaves. Adaxial-side-up orientation significantly promoted embryogenesis in comparison with abaxial-side-up orientation. There was no significant effect of sucrose in a range of concentrations (10–60 g l−1). Modified 1/2-MS medium (containing 85 mg l−1 KH2PO4) supplemented with 170 mg l−1 NaH2PO4 significantly promoted direct somatic embryogenesis. Peptone at 0.5 mg l−1 gave significantly higher emrbyogenic response (80%) on leaf tips than control treatment (50%). The best response on direct embryo formation was obtained on the modified 1/2-MS medium supplemented with 10–20 g l−1 sucrose, 170 mg l−1 NaH2PO4 and 0.5 g l−1 peptone.

Osteoblast culture on polished titanium disks modified with phosphonic acids

Abstract: Titanium is widely used in dental implants due to its suitable physical properties and its good biocompatibility. However, it is integrated into bone only passively, and the resulting fixation in the bone, which is necessary for the function, is mainly mechanical in nature. With the objective of increasing the chemical interaction between the implant and the bone tissue, several phosphonic acids were synthesized and grafted onto titanium disks. Here we report on the proliferation, differentiation, and protein production of rat osteoblastic cells (CRP10/30) on phosphonic-acid-modified titanium surfaces studied in vitro. No statistical differences were found in osteoblast proliferation among the phosphonic-acid-modified titanium, unmodified titanium, and tissue culture plastic (used as a positive control), indicating that the phosphonic acids used were not cytotoxic to the osteoblasts used. For all surfaces (modified or not), the alkaline phosphatase activity was at least as good as it was on tissue culture plastic. However, the total amount of protein, and especially the collagen type I synthesis, was sensitive to surface modification. On titanium modified with ethane-1,1,2-triphosphonic acid, the total amount of synthesized protein was significantly higher than it was on unmodified titanium surfaces. A significant increase (up to 16%) of collagen type I production was observed on titanium surfaces modified with this acid or with methylenediphosphonic acid compared to unmodified titanium surfaces.

Matrix engineering for osteogenic differentiation of rabbit periosteal cells using α-tricalcium phosphate particles in a three-dimensional fibrin culture

Abstract: Tissue engineering using periosteal cells is a promising approach for bioactive bone repair. Of central importance in tissue engineering is the cell–matrix interaction. In the present study we tested in vitro the influence of α-tricalcium phosphate (α-TCP) particles on the expression of osteogenic markers in rabbit periosteal cells embedded in specially manufactured fibrin beads. After cell isolation from tibial periosteum of New Zealand White rabbits, and following monolayer culture, cells were embedded in alginate–fibrin beads containing 7.5% α-TCP particles and, as a control group, in beads without particles. The alginate was extracted immediately after polymerization. The beads were cultivated for at least 53 days. The DNA content, alkaline phosphatase activity, and osteocalcin level were determined. In monolayer culture the number of cells increased 6.5-fold. DNA content increased in both three-dimensional culture groups but was significantly higher in the beads containing α-TCP. Alkaline phosphatase activity increased in both groups without significant differences. Osteocalcin content was significantly higher in the beads containing α-TCP than it was in those without α-TCP. These observations indicate that matrix engineering using inorganic particles in fibrin culture can influence the osteogenic differentiation of mesenchymal cells. The three-dimensional culture system presented here facilitates the preparation of grafts for bone reconstruction. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 690–696, 2002

Plant tissue culture. Biotechnology. Milestones

Abstract: The progress in the development of the technologies of plant tissue and cell culture over the past four decades has been remarkable. This article covers my personal reflections on the various topics and is based on my involvement in the field during that period. There are three fundamental technologies which constitute most of what is referred to as plant in vitro technologies or tissue culture. The origin and some of the key persons involved in the development of each of these procedures will be discussed. The technology that is most common is growing plant tissue on gel-solidified nutrient media. That technology is being used in the most vital procedures, namely the regeneration of plants from cultured cells. The culture of plant cells in liquid suspension was developed very shortly after that, and has become a very effective technology for plant regeneration by somatic embryogenesis. The method of meristem culture arose out of a need for developing plants that were virus-free. In many species the technique is now being used to produce virus-free crop plants. Another important technology is the culture of anthers and microspores for producing haploid and homozygous plants. Included with plant tissue culture is the development of the plant protoplast and cell fusion technologies for the production of new plant hybrids. The final aspect of the development concerns the integration of tissue culture with molecular genetics, which has developed into the rapidly expanding field of biotechnology.

Characterization of a defensin gene expressed in oil palm inflorescences: induction during tissue culture and possible association with epigenetic somaclonal variation events

Abstract: From differential display studies performed on oil palm (Elaeis guineensis Jacq.) tissue cultures bearing or lacking an epigenetic homeotic flowering abnormality, known as mantled, EGAD1, a gene coding for a putative plant defensin, has been identified and characterized. In whole plants, transcripts of the EGAD1 gene were detected only in inflorescences. The closest characterized relative of the oil palm EGAD1 gene is the Petunia PPT gene, which is expressed principally in the pistil of the flower. The 77 amino acid polypeptide encoded by the EGAD1 gene displays strong similarities with a number of plant defensin proteins, which are thought to play a protective role and which have been shown in some cases to possess antifungal properties. Oil palm tissue cultures exhibit a generally strong induction of accumulation of EGAD1 transcripts, which were detected to differing extents at all stages of the tissue culture regeneration process. The 5' flanking region of the EGAD1 gene was found to contain two different types of potential cis-acting DNA element previously identified in the promoters of plant defence-related genes, which may explain the observed expression in tissue cultures. At the callus stage of the in vitro regeneration procedure, a differential accumulation of EGAD1 transcripts was observed which correlated with the presence or absence of the mantled flowering abnormality. EGAD1 gene expression may therefore be a marker of epigenetic somaclonal variation events.

TNF-α Promotes Caspase Activation and Apoptosis in Human Fetal Membranes

Abstract: Purpose: Increased amniotic fluid tumor necrosis factor (TNF) is a marker of infection when associated with preterm labor and preterm premature rupture of the amniochorionic membranes (PROM). We have noted increased apoptosis in membranes derived from women with PROM. This study examines the role of TNF in promoting fetal membrane apoptosis. Methods: Amniochorion (n = 8), collected at the time of elective repeat cesarean section prior to labor from normal term gestation, were placed in an organ explant system. After 48 h in culture, the membranes were stimulated with recombinant TNF-α (20 ng/mL) for 24 h. Tissue frozen after stimulation was subjected to RT-PCR to study the expression of TNF-induced caspase genes. ELISA assayed the levels of proapoptotic p53 in tissues and cell death related nuclear matrix protein (NMP) in tissue culture supernatants. The activity of caspases in tissue homogenates was measured using substrates specific for caspase 2, 3, 6, 8, and 9. Results were analyzed by using the Wilcoxon nonparametric test for paired samples. A p < 0.05 was considered significant. Results: RT-PCR showed induction of caspases 2, 8, and 9 (caspase cascade initiators) in human fetal membranes after TNF stimulation. Caspases 3 and 6 (effector caspases) expression was constitutive in both TNF stimulated- and control membranes. Caspases, 2, 3, 8, and 9 activity was significantly higher in TNF-stimulated tissues compared with control, whereas, no significant change in caspase 6 activity was noticed. TNF-stimulated tissues released increased levels of NMP (24.03 U/mL) compared with control (13.5U/mL) (p = 0.03). TNF also increased p53 levels in the tissues (0.05 ng/mL) compared with control cultures (0.03 ng/mL; p = 0.02). Conclusions: TNF increases proapoptotic p53 levels and caspase activities in fetal membranes. Increased NMP reflects cell death.

Proliferating cells versus differentiated cells in tissue engineering.

Abstract: The efficiency of cell or tissue cultures is usually judged by how quickly confluence is reached within a Petri dish or on a scaffold. Growth factors and fetal bovine serum are employed to drive cultured cells from one mitosis to the next as quickly as possible. The tissue specific interphase is extremely short under these conditions, so that the degree of differentiation desired in tissue engineering cannot be achieved. To reach the goal of functional differentiation in vitro mitosis and interphase must be separated experimentally and tailored to the specific requirements of the cell-type used. This could be achieved by a three step concept for tissue-engineering in vitro as we present here. The expansion phase is followed by a phase in which tissue differentiation is initiated. The final phase serves to express and maintain histotypical differentiation of the generated tissue.

Effects of anti-inflammatory drugs and preservatives on morphologic characteristics and migration of canine corneal epithelial cells in tissue culture.

Abstract: Objective To determine the effects of commonly used ophthalmic corticosteroids, suprofen, polysulfated glycosaminoglycan and preservatives on morphologic characteristics and migration of canine corneal epithelium grown in cell culture. Animals studied Corneal epithelial cells harvested from the corneas of euthanized dogs were propagated in cell culture. Procedures Canine corneal epithelium was grown in tissue culture. The cells were treated with different corticosteroids, polysulfated glycosaminoglycan, suprofen or preservatives at different concentrations after a defect was created in the monolayer. Cellular morphologic characteristics and closure of the defect were compared between test drugs and controls. Results Morphologically the cells treated with dexamethasone were essentially the same as controls. Prednisolone and hydrocortisone caused rounding and shrinkage of the cells. Both suprofen and polysulfated glycosaminoglycan caused no apparent changes in morphologic characteristics at the lowest concentrations tested, but at higher concentrations there was a concentration-dependent degree of rounding and shrinkage. Benzylkonium chloride and thimerosal caused rounding and shrinkage of all the cells at all concentrations tested. Dexamethasone, hydrocortisone, and suprofen did not inhibit epithelial migration over the defects at the lowest concentrations tested. All other drugs and concentrations inhibited cellular migration. Conclusion Dexamethasone affected the morphologic characteristics and migration of corneal epithelial cells less than hydrocortisone and prednisolone; therefore, dexamethasone may be the drug of choice when a corticosteroid is indicated and an epithelial defect is present. Suprofen and polysulfated glycosaminoglycan caused a concentration-dependent effect on morphologic characteristics and migration. The preservatives caused severe changes and inhibited migration of the canine corneal epithelial cells at all concentrations and may therefore contribute to poor epithelialization of ulcers treated with preservative-containing drugs.

Characterization of Mitotic Neurons Derived From Adult Rat Hypothalamus and Brain Stem

Abstract: Embryonic or neonatal rat neurons retain plasticity and are readily grown in tissue culture, but neurons of the adult brain were thought to be terminally differentiated and therefore difficult to c...

The role of c-fos in cell death and regeneration of retinal ganglion cells.

Abstract: Purpose To investigate the effect of c-fos on apoptotic cell death and regeneration of damaged retinal ganglion cells (RGCs) in tissue culture of retinal explants Methods Retinas from transgenic mice carrying the exogenous c-fos gene under the control of the interferon (IFN)-alpha/beta inducible Mx-promoter (Mx-c-fos), c-fos-deficient mice, and littermate control mice were dissected and cultured in a three-dimensional collagen gel culture system, followed by an analysis of TdT-dUTP terminal nick-end labeling (TUNEL) staining and measurement of neurites that emerged from explants Results Compared with littermate control mice, Mx-c-fos transgenic animals showed a higher ratio of TUNEL positivity in the RGC layer from early in the culture period that correlated with the small number of regenerating neurites In contrast, the c-fos-null mutated mice showed a still-lower ratio of TUNEL-positive cells Nevertheless, the number of regenerating neurites was significantly lower in the initial phase, although the drastic increase in density of neurite regeneration was observed in the late period of culture Conclusions These findings suggest that c-fos is involved in both apoptotic cell death and regeneration of damaged RGCs Elucidation of the precise c-fos-mediated cascade involved in RGC apoptosis and regeneration is significant in realizing neuronal survival and regeneration

Generation of a life-expanded rhesus monkey fibroblast cell line for the growth of rhesus rhadinovirus (RRV).

Abstract: RRV, the rhesus macaque equivalent to HHV-8 or kaposi's sarcoma-associated herpesvirus (KSHV) was recently isolated from a simian immunodeficiency virus (SIV) infected macaque with a lymphoproliferative disorder. The growth of RRV in tissue culture requires propagation of primary rhesus monkey fibroblasts (RFs). In an effort to extend the life of these primary cells in tissue culture, the catalytic subunit of telomerase (hTERT) was introduced into RF cells using a recombinant retrovirus. This new cell line, Telo-RFs, have currently been passed in tissue culture over 80 times compared to a maximum passage number of 38 for wild type RFs, remain fully permissive for RRV DNA replication and production of infectious virus. Viral gene expression of immediate-early and early RNA transcripts was virtually identical to that observed in wild-type (wt) RFs. In addition, transfection experiments show that telo-RFs are easily and more efficiently transfected than wtRFs.

Composition and methods fro the production of biological tissues and tissue constructs

Abstract: The present invention relates to compositions and methods for preparing tissues or tissue constructs. In selected embodiments, the invention relates to the construction of a multi-layered biological structure (i.e. system) that includes a cellular support matrix seeded with living cells derived from a native tissue. The present invention also relates to tissue culture protocols to promote the in vitro growth of tissues and tissue constructs.

Addition of nickel to Murashige and Skoog medium in plant tissue culture activates urease and may reduce metabolic stress

Abstract: Nickel has been identified as an essential element for plant growth. The lack of nickel and the inclusion of cobalt leads to absence of urease activity in plants grown on MS medium in tissue culture. To avoid leaf damage and metabolic stress, nickel should be included in tissue culture growth media.